Andrew Newell

Last seen: 2 years ago | Active since 2011

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A geophysicist who uses MATLAB for most of his modeling. Professional Interests: geophysics

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Using AND Operator in “if” statements
The problem is that size returns a vector: size([1 2 3]) ans = 1 3 Instead, use |numel|: if numel([1 2 3])==numel([4 5 6]) &...

13 days ago | 9

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How do I generate a random number with beta distribution?
You can use the function betarnd, but you'll need to do some normalizing to get it in the standard form used by MATLAB (see Beta...

3 years ago | 0

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Newton Raphson - saving all values and using last iteration value as initial for next
Sorry, I just realized that you wanted to save the iterations. Here's how: x = -0.001*ones(6,length(A1)); for i=1:5 x(i+1...

3 years ago | 0

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Newton Raphson - saving all values and using last iteration value as initial for next
O.k. So here is how you do it: x = -0.001*ones(size(A1)); for i=1:5 x = x - f(x)./fd(x); end

3 years ago | 0

Answered
Finding tangent plane with the max range value and z value being equal
Notice that is empty, then try this: X = -1.41:0.01:1.41; [~,idx] = min(abs(X-1)); disp(X(idx)-1) This being floating point...

3 years ago | 0

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Answered
MatCont for Homotopy Method
The primary purpose of MatCont (which is a GUI front end for Cl_MatCont) is to analyze solution curves of the form . These may b...

4 years ago | 0

Answered
Coupled Differential Equations - derivatives on both sides of equations
Let's simplify things a little bit so we can better see what is going on. Let Y = [x; y]; G1(t,Y) = 0.000053+g1(Y(1),t...

7 years ago | 0

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Why doessn't my code work for compsite simpson one third rule?
You weren't defining the function properly. Try this: func=@(x) 1+exp(-x); See <https://www.mathworks.com/help/matlab/ma...

7 years ago | 0

Answered
how to continue code in next line with comment between them
You can have the comments beside each part instead: a=b+c+f... % line 1 +t+h+k; % line 2 However, it is possib...

7 years ago | 0

Answered
Class Property: Array of Objects
You need to define a get method (see <https://www.mathworks.com/help/matlab/matlab_oop/access-methods-for-dependent-properties.h...

7 years ago | 0

Answered
Series Summation With Function Handles
In principle, you can use |matlabFunction| to get around this difficulty. However, I noticed a couple of issues. First, the summ...

7 years ago | 1

Answered
How to overlay a curve over histogram?
If you already have the curve, then just type |hold on| and plot it. An example: ydata = randn(1000,1); hist(ydata) hold ...

7 years ago | 0

Answered
How to create a new variable for each iteration of a while loop?
Structures are great for this kind of task (see <https://www.mathworks.com/help/matlab/ref/struct.html struct>). Here is an exam...

7 years ago | 1

Answered
How to store multiple serial objects
You certainly can store them in an array, e.g.: n = 8; s = cell(8,1); for ii=1:8 s{ii} = serial(sprintf('COM1%d',ii-...

7 years ago | 1

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How can I fix my error with the passing a function to another fuction?
The first line should be f = @(x) exp(x);

7 years ago | 0

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Integration of norminv function
The problem is that |norminv(x,0,1)| goes to |-Inf| as |x| goes to zero and |Inf| as |x| goes to 1 (and ditto for |y| and |z|), ...

7 years ago | 1

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How to plot a matrix in polar coordinates with color?
I think most approaches will involve converting the coordinates to Cartesian. Here is one approach: v0=10; A=4.*v0./pi;k=1;...

7 years ago | 1

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Answered
Nonlinear Tangent (trigonemetric) equation
Before trying to find zeros for a function, it's a good idea to plot it so you understand the nature of the problem. If you do t...

7 years ago | 0

Answered
How to calculate the integral of a function with a spline in it
For evenly or unevenly spaced data, you could use the trapezoidal rule (MATLAB function <https://www.mathworks.com/help/matlab/r...

7 years ago | 0

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Offseting the y axis to make data more clear
After yyaxis right; use a command like ylim([-0.1 1.5]) to move the axes.

7 years ago | 0

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Logical Test on Matrix Failing
The variable |little_endian_message| is a char representation of binary numbers. Try this: if( little_endian_message(a) =...

7 years ago | 0

Answered
Plots with stairs and inclines?
I'm not sure how you intend to generate the points, but for the example plot you gave, |plot| works just fine with an appropriat...

7 years ago | 1

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Quiver Plot Arrows too Wide
Have you tried looking at <https://www.mathworks.com/help/matlab/ref/quiver.html the documentation for quiver>? There is an opti...

7 years ago | 0

Answered
Collection many vectors in one matrix
The answer is G = [I1; I2; I3]; See <https://www.mathworks.com/help/matlab/math/creating-and-co%E2%80%A6 Creating and Co...

7 years ago | 1

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How can I speed my function?
One source of delays can be |repmat|. This can be replaced by a suitable choice of index, as in the following: r = R(i,:); ...

7 years ago | 1

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Answered
Overwriting While-loop conditional with +Inf
MATLAB evaluates a logical expression like your |while| condition from left to right. If |a==1|, it knows the expression is fals...

7 years ago | 0

Answered
How to Simplify an symbolic expression
If I define a= 2*atan((-2+sqrt(4-gama^2 *l^2* M^2-4* gama *l* M^2 *tan(gama/2)+4* tan(gama/2)^2-4 *M^2 *tan(gama/2)^2))/(ga...

7 years ago | 0

Answered
How to load *.mat file from each directories in new script?
Here is a solution that assumes there is one of these |.mat| files in every subdirectory of each of the 15 directories. Let's al...

7 years ago | 0

Answered
Old form of legend('string 1','string 2',2) ??
Actually, it's NW (see the <http://www.mathworks.com/help/releases/R13sp2/techdoc/ref/legend.html?s_tid=srchtitle documentation ...

7 years ago | 1

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Answered
Finding normals to contours on contour plot
You want curves to follow the gradients. It's easy enough to <https://www.mathworks.com/help/matlab/creating_plots/display-quive...

7 years ago | 0

Andrew Newell

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